Microwave Pretreatment of Peanuts Modulates Oil Body Emulsion Stability: Mechanism and Application as a Source Modification Strategy for Efficient Demulsification

This study investigated microwave pretreatment (0-900 W) of peanuts as a source modification strategy to reduce the stability of peanut oil body emulsions (POBEs) and improve aqueous enzymatic extraction. Results indicated that higher power treatment (≥540 W) significantly destabilized POBE. The optimal condition at 720 W increased POBE extraction yield and demulsification rate by 16.82% and 46.32%, respectively, compared with the control. This destabilization was attributed to marked changes in interfacial properties, including decreased apparent viscosity, lowered absolute ζ-potential (from 35.93 mV to 27.09 mV), increased particle size (from 1177.16 nm to 1976.98 nm), and the microstructure of droplet aggregation. Compositional analysis revealed that microwave treatment induced POBE reorganization, characterized by increased lipid and phospholipid contents alongside reduced moisture, solid, and protein levels. Further interfacial protein analysis revealed that exposure triggered protein conformational unfolding, hydrophobic group exposure, and subsequent aggregation, which weakened protein adsorption at the interface and reduced the mechanical strength of the interfacial film. These findings elucidate the mechanism of microwave-induced emulsion instability, providing a theoretical basis for enhancing oil extraction efficiency through raw material pretreatment.